Idlescan is a IP id port scanner, written to demonstrate that machines should not have a predictable ip.id increments. Features: Target never sees your ip address, No limit in the number of sensors working in parallel, Automatic windows ip.id increment detection (windows counts in little endian), and Auto-dropping sensors with traffic.
You can download it from the following link: https://packetstormsecurity.com/files/download/11244/idlescan-v0.1-alpha3.tgz
Source: https://packetstormsecurity.com/files/11244/idlescan-v0.1-alpha3.tgz.html